Denver Broncos quarterback Tim Tebow celebrates with Eddie Royal and Orlando Franklin (74) after his fourth-quarter, 2-point conversion during an NFL football game against the Miami Dolphins on Sunday, Oct. 23, 2011, in Miami. The Broncos won 18-15 in overtime. (AP Pho[auth] to/Miami Herald, Joe Rimkus Jr. ) MAGS OUT

ENGLEWOOD, Colo. (AP) — Although Tim Tebow’s mechanics are far from polished and his passes far from pretty, his moxie appears to be in perfect working order.

When the game’s on the line, the Denver Broncos’ charismatic quarterback finds a way to rally his team, happy feet in the pocket and all.

Tebow, in his first start of the season, pulled off an improbable comeback Sunday, bringing the Broncos back from a 15-0 deficit in the waning minutes of regulation for an 18-15 overtime win over winless Miami.

With this implausible victory, the popularity of Tebow is only going to skyrocket — as if it weren’t sky high already.

Many fans have long wanted Tebow as their starter, even going so far as to put up billboards begging coach John Fox to insert the former Heisman Trophy winner from Florida.

They got their wish against San Diego two weeks ago when Fox yanked Kyle Orton in favor of Tebow, who almost rallied the Broncos to a win in the fourth quarter.

This time, Tebow succeeded.

And with a comeback for the ages, too.

The Broncos said it’s the largest deficit overcome in a win with less than 3 minutes since the 1970 NFL merger, citing the Elias Sports Bureau.

“He’s a guy who’s going to continue to fight, continue to scrap and use his arm, his legs or whatever to get the job done,” safety Brian Dawkins said after the game.

That’s the thing about Tebow: He may not always look pretty and perfect, but he can find a way to get the job done. It’s a quality that just may be his strongest.

He also wears his emotions on his sleeve, even if his left arm doesn’t always deliver the most accurate of passes. He’s been scrutinized and chastised by skeptics since he was drafted by the Broncos with the 25th pick in 2010. Not because of his work ethic — that’s never questioned — but because of his unorthodox style.

But what he lacks in smoothness he tries to make up for in leadership.

“There’s one thing you can say about this team is that we have a lot of heart. We have a lot of courage. We’re going to fight until the end and continue to believe,” Tebow said. “It’s my fault that we were in that position in the first place. I just have to play better in the first three quarters so we don’t have to make that comeback in the fourth.”

Fox certainly wouldn’t mind that.

Tebow was having a lackluster day until midway through the fourth quarter. He was missing backs on simple screens and overthrowing wide open receivers down the field. Tebow was 4 of 14 for a paltry 40 yards before finding his touch late with 5:23 remaining.

Asked if he’s the starter from here on, Fox danced around a direct response.

“I can’t predict the future,” he said. “He’s the starter right now.”

Once burned, twice shy. After all, Fox has had his own words come back to bite him before. Leading into the season, he said over and over that Orton gives the team the best chance to win.

And now Tebow has taken over.

So, does he give them the best chance?

“I’ll probably never use that statement again,” Fox said. “It does get thrown back at me quite a bit.”

Hard to argue with the result.

But Tebow had plenty of help, starting with receiver Demaryius Thomas, who made a sprawling catch for the first score with 2:44 left.

Later, after the Broncos recovered an onside kick, tight end Daniel Fells hauled in a diving catch near the goal line to set up another score in which Fells caught a 3-yard TD toss. Tebow took it from there as he ran in the 2-point conversion to tie the game with 17 seconds remaining.

Once in overtime, Denver’s D.J. Williams sacked Matt Moore to force a fumble and recovered it at the Miami 36. Matt Prater clinched the win with a 52-yard field goal after missing two earlier in the game.

It was only fitting since this was Tebow’s day at the stadium. Technically, the ceremony was to honor the 2008 national champion Florida squad, but it seemed like Tebow’s moment anyway.

“He’s an incredible guy, for sure,” Fox said. “I think he does have great intangibles.”

Tebow’s spunk overrides his wobbly spirals. He’s rallied teams before — high school, college and now in the NFL — so his belief never wavers, no matter how much time is left or the size of the deficit.

“That’s something as a football player and as an athlete — you can’t lose confidence in yourself. If you do, you’ve lost already,” Tebow said. “I kept believing in the people around me and that eventually we were going to be able to start to get things going and eventually we did.

“I think what really helps is when you believe in the people around you and the guy next to you.”

This was against a winless team, though.

It could be a different story next weekend against Detroit, a team that’s dropped two straight after starting 5-0.

“I need to get a lot better,” Tebow said. “That’s my job as the quarterback to correct it. I believe we’ll put in the work to do that.”

Notes: Leading rusher Willis McGahee is expected to have surgery later this week for a broken finger on his right hand and will not play against Detroit. McGahee didn’t return after hurting the finger in the third quarter of the overtime win over the Dolphins. He finished with 76 yards on 18 attempts. … Defensive ends Robert Ayers (knee) and Elvis Dumervil (ankle) also were banged up against the Dolphins. Fox said Monday that more information on their status would be available later in the week.